What mysterious building project is China engaged in the South China Sea?

China is moving tonnes of sand in the South China Sea, but they’re not playing at building sandcastles. And the Chinese government have no intention of knocking these structures down when they’re finished.

Thanks to these aerial images captured by the Asia Maritime Transparency Initiative, we’ve been able to get a closer look at what’s going on in the South China Sea.

The Asian giant is creating seven new artificial islets on the reefs. Last July, the Chinese government announced that they’d soon be finished.

Most of the islets already boast airstrips, military bases, and port facilities. Their reason for being there is strategic: China needs logistical support to defend its interests on the Spratly Islands, whose ownership they dispute with the Philippines, Vietnam, Malaysia and Taiwan.

These countries have been expanding the size of their islands too, though not on the same scale as their great neighbour. Vietnam is also expanding a nearby islet.

Here’s a look at how a reef is transformed into a Chinese island in under a year. From August 2014 to May 2015.

Building artificial islets seem to be the latest trend in the luxury ‘real estate’ market (check out Dubai’s), but they also serve as an expansion strategy for countries with border conflicts.

In short, China is using these reefs, almost 500 miles from its southern coast, to increase its territory.

The ecological catastrophe of the act is undeniable, but the operation has multiple benefits for the Chinese: it enables them to exploit a remote sea region that, until recently, had been beyond anyone’s reach. That means fishing, gas, and oil.

As long as no one puts a stop to this strategy, the island-expanding rivalry will continue to grow. These days, one country doesn’t need to invade another to gain new territory. It can simply make itself more land – as easily as building castles on the sand.